JP2019138388A - Sealing device - Google Patents

Abstract

To provide a sealing device which can reduce an expansion force without decreasing a collapse margin, and can reduce slide resistance which is generated at slide movement.SOLUTION: A sealing device 1 is attached to an attachment groove 52 formed at an opposing face 51a of one member 51 out of two members which oppose each other, and relatively move, and slidably contacting with an opposing face 53a of the other member 53. The sealing device 1 comprises: one peripheral face 1a in a radial direction which is annularly formed of a rubbery elastic body, and opposes a groove bottom face 52a of the attachment groove 52: the other peripheral face 1b in the radial direction which slidably contacts with the opposing face 53a of the other member 53, and is formed into a circular arc shape at a cross section; one end face 1c in an axial direction; and the other end face 1d in the axial direction. An annular recess 2 is formed which is opened at one end face 1c in the axial direction, and an annular seal protrusion 3 is formed between the recess 2 and one peripheral face 1a in the radial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealing device according to a sealing technique. The sealing device of the present invention is used, for example, as a piston seal in a hydraulic cylinder for use in construction machinery, industrial machinery, or automobiles.

  Conventionally, as shown in FIG. 4, the hydraulic cylinder is mounted in a mounting groove 52 provided on the outer peripheral surface 51 a of the piston 51, and slidably contacts the inner peripheral surface 53 a of the cylinder 53. 2. Description of the Related Art A sealing device 1 that exhibits a sealing function so that a sealing target such as heavy oil does not leak is known.

  The sealing device 1 is formed in an annular shape by a rubber-like elastic body such as rubber or urethane. Further, the sealing device 1 includes a cylindrical inner peripheral surface 1a facing the groove bottom surface 52a of the mounting groove 52, an outer peripheral surface 1b having a circular arc cross section that slidably contacts the inner peripheral surface 53a of the cylinder 53, It has a high-voltage side end surface 1c and a low-pressure side end surface 1d that are planar at right angles to the axis, and is formed in a D-shaped cross section.

JP 2006-316947 A JP 2004-125099 A

  Since the sealing device 1 sets a crushing margin for the inner peripheral surface 53a of the cylinder 53, the sealing device 1 is compressed in the radial direction when mounted in the mounting groove 52, and the expansion force (repulsive force) generated at this time causes the cylinder 53 to be compressed. It is pressed against the inner peripheral surface 53a and exhibits a sealing function.

  However, in the squeeze packing type sealing device 1 used for reciprocation, the crushing allowance is set larger than that of the lip packing type sealing device, and accordingly, the expansion force is also set large. Therefore, there is a concern that the sliding resistance generated during sliding increases (sliding resistance = expansion force × friction coefficient), and sliding heat generation increases or sliding wear tends to occur.

  Note that, by reducing the cross-sectional area of the sealing device 1, the crushing allowance is reduced, so that the sliding resistance can be reduced. In this case, however, there is a concern that the sealing performance may be reduced.

  In view of the above, it is an object of the present invention to provide a sealing device that can reduce the expansion force without reducing the crushing allowance and can reduce the sliding resistance generated during sliding. To do.

  In order to solve the above-mentioned problems, the sealing device of the present invention is mounted in a mounting groove provided on the facing surface of one of the two members facing and moving relative to each other, and can slide on the facing surface of the other member. A sealing device that contacts the outer surface of the mounting groove, and is slidably in contact with one circumferential surface facing the groove bottom surface of the mounting groove and the facing surface of the other member. In a sealing device comprising a radially outer circumferential surface having an arc-shaped cross section, one axial end surface, and the other axial end surface, an annular concave opening is provided in the axial one end surface, and the concave portion An annular seal protrusion is provided between the one circumferential surface in the radial direction.

  As an embodiment, in the sealing device described above, the seal protrusion has an angle with respect to the groove bottom surface by providing the seal protrusion with a protruding portion that protrudes in a radial direction rather than the one peripheral surface in the radial direction. It is characterized by being formed as a seal lip that comes into contact.

  In the present invention having the above-described configuration, the recess is provided so as to open to the end face of the sealing device, and the seal protrusion is provided between the recess and the peripheral surface, so that the filling rate of the sealing device with respect to the mounting groove decreases. In addition, the seal protrusion can be easily deformed when the sealing device is mounted in the mounting groove. Therefore, the expansion force can be reduced without reducing the crushing allowance, and the sliding resistance generated during sliding can be reduced. Accordingly, it is possible to suppress or eliminate the concern that the sliding heat generation becomes large or the sliding wear is likely to occur.

Sectional drawing of the principal part of the sealing device which concerns on embodiment Cross-sectional view of the relevant part showing the sealing device mounted in the mounting groove Cross-sectional view of the main part showing a state in which the pressure to be sealed acts on the sealing device Sectional drawing of the principal part which shows the state which mounted | wore the mounting groove with the sealing device which concerns on background art

  As shown in FIGS. 1, 2, and 3, the sealing device 1 according to the embodiment includes a mounting groove provided on an outer peripheral surface (opposing surface) 51a of a piston (one member in claim 1) 51 in the hydraulic cylinder device. 52 and is slidably in contact with the inner peripheral surface (opposing surface) 53a of the cylinder (the other member) 53, so that pressure oil or the like is transferred from one axial high pressure side H to the other axial low pressure side L. The sealing function is exhibited so that the object to be sealed (not shown) does not leak.

  The mounting groove 52 is formed in an annular shape, and has a cylindrical groove bottom surface 52a, a high-pressure side groove side surface 52b, and a low-pressure side groove side surface 52c that are perpendicular to the axis, and has a rectangular cross section.

  The sealing device 1 is formed in an annular shape by a rubber-like elastic body such as rubber or urethane. Further, the sealing device 1 includes a cylindrical inner peripheral surface (one peripheral surface in the radial direction) 1 a facing the groove bottom surface 52 a of the mounting groove 52 and a cross-sectional circle that slidably contacts the inner peripheral surface 53 a of the cylinder 53. An arc-shaped outer peripheral surface (the other peripheral surface in the radial direction) 1b, a high-voltage side end surface (one end surface in the axial direction) 1c and a low-pressure side end surface (the other end surface in the axial direction) 1d having a plane perpendicular to the axis It is formed in a letter shape. The sealing device 1 is also referred to as packing, and is also referred to as a D-ring because of its cross-sectional shape.

  The sealing device 1 includes an annular recess 2. The depth of the recess 2 is set in the axial direction so as to open to the high-pressure side end surface 1c, and the position close to the inner peripheral surface 1a in the high-pressure side end surface 1c (the center in the radial direction of the high-pressure side end surface 1c). (Position on the inner peripheral side). The recess 2 is formed in a cross-sectional shape in which the width (radial width) gradually becomes narrower from the recess opening to the recess bottom. The recess 2 is also called a U-shaped groove because of its cross-sectional shape.

  Along with the provision of the recess 2 so as to open to the high-pressure side end surface 1c, an annular seal projection 3 is provided between the recess 2 and the inner peripheral surface 1a. As the height is set in the axial direction, the height is set in the same axial direction. The seal protrusion 3 is formed in a cross-sectional shape in which the width (radial width) gradually increases from the protrusion distal end to the protrusion base end. The width of the seal protrusion 3 is smaller than the height of the seal protrusion 3, and thus the seal protrusion 3 is formed in a thin shape.

  Further, a protruding portion 4 is provided on the inner peripheral surface of the seal protrusion 3 so as to protrude further toward the inner peripheral side than the inner peripheral surface 1a, whereby the seal protrusion 3 has a predetermined width with respect to the groove bottom surface 52a. It is formed as a seal lip that contacts with an inclined angle. The protrusion 4 functions as a lip tip in the seal lip.

The width (total axial width) w ₁ of the sealing device 1 is smaller than the width (total axial width) w ₅₂ of the mounting groove 52. Therefore, the filling rate of the sealing device 1 with respect to the mounting groove 52 is set to be smaller than 100%.

The outer diameter _{d 1} of the sealing device 1 is formed larger than the inner diameter _{d 53} of the cylinder 53. Accordingly, the sealing device 1 is set with a margin for the inner peripheral surface 53 a of the cylinder 53.

The inner diameter _{d 2} of the sealing device 1 has been equally formed and the diameter _{d 52} of the groove bottom surface 52a of the mounting groove 52, the seal projection 3 diameter of the groove bottom 52a of the inner diameter _{d 3} is the mounting groove 52 in the projection 4 It is formed smaller than d _52. Therefore, the sealing device 1 is set with a squeeze margin for the groove bottom surface 52 a by the seal protrusion 4.

  In the sealing device 1 having the above configuration, the annular recess 2 is provided so as to open to the high-pressure side end surface 1c, and the annular seal protrusion 3 is provided between the recess 2 and the inner peripheral surface 1a. The filling rate of the sealing device 1 with respect to the mounting groove 52 is reduced as compared with the case where there is no recess, and the seal protrusion 3 can be easily deformed when the sealing device 1 is mounted in the mounting groove 52. . Therefore, the expansion force (repulsive force) of the sealing device 1 can be reduced without reducing the crushing allowance with respect to the inner peripheral surface of the cylinder 53, and thus the sliding resistance generated during sliding can be reduced. Therefore, it is possible to suppress / eliminate sliding heat generation and sliding wear.

  Further, since the seal protrusion 3 is formed as a seal lip that contacts the groove bottom surface 52a with a predetermined inclination angle, when the sealing device 1 is mounted in the mounting groove 52 as shown in FIG. As a whole, the expansion force is further reduced by tilting obliquely and reducing the amount of squashing. Therefore, the sliding resistance generated during sliding can be further reduced.

  In addition, since the interference allowance with respect to the groove bottom surface 52a by the seal protrusion 3 is set, the sealing device 1 has a small behavior in the mounting groove 52, and the outer peripheral surface 1b is formed in a circular arc shape (full R shape). Therefore, even if the sealing device 1 is inclined, the generated surface pressure form on the inner peripheral surface 53a of the cylinder 53 does not change greatly. Therefore, the influence on the sealing performance is small.

  As shown in FIG. 3, when the sealing target pressure P acts, the sealing device 1 is pressed against the low-pressure side groove side surface 52c as a whole (arrow A), and the pressure P is introduced into the recess 2 to open the recess 2. The outer peripheral surface 1b is pressed against the inner peripheral surface 53a of the cylinder 53 (arrow B), and the seal protrusion 3 is pressed against the groove bottom surface 52a (arrow C). Accordingly, the contact surface pressure is increased at each of the inner and outer circumferences, and the seal surface pressure is increased, so that good sealing performance can be exhibited.

  Also, as shown in FIG. 3, when the sealing device 1 is pressed against the low-pressure side groove side surface 52c as a whole, the posture in the mounting groove 52 is stabilized, so that good sealing performance can also be exhibited.

1 Sealing device 1a Inner peripheral surface (radial one peripheral surface)
1b Outer peripheral surface (the other peripheral surface in the radial direction)
1c End face on the high pressure side (one end face in the axial direction)
1d Low pressure side end surface (the other end surface in the axial direction)
2 Concave part 3 Seal protrusion 4 Protrusion part 51 Piston (one member)
51a Peripheral surface (opposite surface)
52 Mounting groove 52a Groove bottom surface 52b High pressure side groove side surface 52c Low pressure side groove side surface 53 Cylinder 53a Inner peripheral surface (opposing surface)
H High pressure side L Low pressure side

Claims (2)

A sealing device that is mounted in a mounting groove provided on the facing surface of one of the two members that face each other and moves relative to each other and that slidably contacts the facing surface of the other member,
It is formed in an annular shape by a rubber-like elastic body, and has one radial circumferential surface facing the groove bottom surface of the mounting groove and the other radial radial cross section in slidable contact with the opposing surface of the other member. In a sealing device comprising a peripheral surface, one axial end surface, and the other axial end surface,
A sealing device comprising: an annular recess opening on one end face in the axial direction; and an annular seal protrusion provided between the recess and the one circumferential surface in the radial direction. The sealing device according to claim 1.
The seal protrusion is formed as a seal lip that contacts the groove bottom surface at an angle by providing the seal protrusion with a protrusion that protrudes in a radial direction from the one circumferential surface of the radial direction. apparatus.

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